1. Field of the Invention
The present invention relates to a front bumper system for a vehicle, which meets the conflicting requirements for both pedestrian safety and 5 mph impact performance.
2. Background
In the past decade, there have been a multitude of advancements for motor vehicle safety. From dual stage airbags and load limiting seatbelts to side airbags and head curtains, occupants of motor vehicles have never been more protected. However, pedestrians still have the same risks they have faced for years.
Automobiles are designed with the safety of their occupants in mind. The increasingly stronger structures that protect these occupants in high-speed frontal crashes however, have devastating effects when the object that is struck is an unprotected pedestrian. In the United States alone in 1997, there were 5,307 fatalities and some 77,000 injuries of pedestrians. Although pedestrian accidents only account for 2.4 percent of all automotive accidents in the U.S., they account for 12.6 percent of all automotive fatalities. In addition to the 5,000 annual fatalities in the U.S., there were over 3,000 in Japan, 7,000 in the European Union, and 19,000 in China.
In order to address this global problem, the European Enhanced Vehicle-Safety Committee (EEVC) working group established test procedures for evaluating the safety performance of motor vehicles with respect to pedestrians. These procedures include the evaluation of bumper systems.
For some off-road and multi-purpose vehicles, an “alternative upper legform impactor test” is used to evaluate the front bumper system. This test propels an upper legform impactor into a stationary vehicle at a high velocity of 40 km/h. Acceptance criteria are based on peak loads and bending moments measured on the impactor. “Alternative upper legform tests” of standard Sport Utility Vehicles' (SUVs') front bumper systems may reveal a very high peak force of 26 kN and a very high peak moment of 1686 Nm. Generally, substantial “soft” crush space is required for good performance. In addition, a series of low speed barrier impact tests are conducted to evaluate vehicle repair costs. This includes frontal impact tests conducted at 5 mph on both flat and 30° angled barriers. Limiting the amount of barrier intrusion into the bumper for the 5 mph flat and angled barrier impacts minimizes repair costs. The low speed barrier testing for a standard SUV bumper system allows an intrusion of 110 mm for the flat barrier test and an intrusion of 90 mm for the angled barrier test.
In order to improve the safety of pedestrians, while conforming to the requirements for bumper impact performance, the inventors of the present invention have developed the vehicle pedestrian safety bumper system that can be used on various types of vehicles including a sport utility vehicle as well as have an excellent 5 mph impact performance.